Ferrer fights hard for Doha win
David Ferrer recovered from a slow start to ease into the quarter-finals of the Qatar Open in Doha at the expense of Tobias Kamke.
The Spaniard went down a break early in the first set against the German qualifier to trail 1-3, but rallied with five games in a row to take the first set before pulling clear in the second for a 6-3 6-2 win.
Second seed Richard Gasquet had to fight hard before prevailing in three sets against Slovenia's Grega Zemlja.
The unseeded Zemlja served for the match at 5-3 in the deciding set, but Gasquet chose that moment to raise his game, breaking to love before powering to a 6-7 (7/9) 6-4 7-6 (7/3) victory in two hours and 44 minutes.
Former champion Nikolay Davydenko defeated fellow Russian Mikhail Youzhny in straight sets in their second-round encounter.
Davydenko, the world number 44, prevailed 7-5 6-3 against the fourth seed, breaking serve twice on his way to victory in one hour and 40 minutes.
The 31-year-old Davydenko has a stellar record in Doha, having beaten Roger Federer and Rafael Nadal on his way to the title in 2010 and finishing runner-up in 2011.
Philipp Kohlschreiber was another seed to fall as he went down in three sets to Frenchman Gael Monfils.
Kohlschreiber, the third seed from Germany, battled hard against a player who had beaten him seven times in eight previous meetings, but could not prevent last year's beaten finalist taking a 6-4 2-6 6-4 win in a shade over two hours.
Monfils will next face another German in Daniel Brands, who saw off Egyptian wild card Mohamed Safwat 4-6 6-3 6-2.
Sixth seed Viktor Troicki also bowed out, losing 6-3 7-5 to Lukas Lacko, while Paolo Lorenzi beat Lukas Rosol 6-0 6-4 and Simone Bolelli ousted Lukasz Kubot 2-6 6-4 6-4.